It may be that Kenne Bell's new throttle body is the largest production Ford throttle body ever. At 168mm along its major axis, it's a monster all right. Conceptually it's a pair of 80mm throttle bodies(!) with the center cut out, according to Kenne Bell's main man Jim Bell, so think of it as twice as large as Ford's 80mm Coyote mouthpiece. Jim says the unit flows 2,150 cfm by itself, and 2,350 cfm if you put a flared entrance on it. That's 1,500hp territory, so if you can't make power, it isn't the throttle body's fault.
The main trick with huge throttle bodies is making them driveable, especially near idle. This is simple physics due to the tremendous perimeter area of the big throttle blade. Barely crack it open and you have too much air, making the throttle touchy to the driver and impossibly responsive for the engine management computer to use for idle control.
Well, impossibly responsive until you dampen the engine with retarded ignition timing, says Jim. Once that was figured out, the barn door of a throttle body was ready to idle placidly at stock rpm. We did not drive Frank's car, but Frank and Kenne Bell techs say it's smooth as stock.
Jim Bell reports the throttle body is in stock and shipping now. The $799 includes the throttle body, adapter plate to bolt it to the Mammoth intake, and a Hypertech handheld programmer with the necessary tune.
To demonstrate the new throttle body Kenne Bell set up a simple test at nearby GTR Performance. Frank Lanzas black GT was once again strapped to the rollers--Frank's car prototyped the Kenne Bell manual-transmission 5.0 kit--and the stock and Kenne Bell throttle bodies were run. Additionally, we tried three different blower pulleys to show how the power gain increases with growing power.
There were no problems or unexpected delays. Swapping the throttle bodies and pulleys was straightforward, and the only other work was downloading the necessary tunes for the stock or KB throttle bodies as necessary. (There's no way the big KB throttle body will operate with the same tune as the stocker.) Downloading is done in the usual Kenne Bell fashion, with a Hypertech handheld.
Details of the results are in the nearby sidebars, but suffice it to say the new throttle body supports power into the 600hp range with laughable ease. More boost and power are coming with a smaller crank pulley/harmonic damper combination and a reinforced oil pump, but that's a story for another time.
Horse Sense: Normally Kenne Bell would have hosted this test on its in-house Dynojet, but it was tied up with another long-term project. Luckily GTR is just around the corner from Kenne Bell and has its own Dynojet, hence the neighborly visit.
On the Dyno
With Ford supplying near-race engines to the showroom floor and aftermarket specialists such as Kenne Bell delivering well-engineered blower packages, it's getting ridiculously easy to dial in nearly any power level desired. Furthermore, there's no need to split hairs in this throttle body test. Each step shows a clear step up the power ladder, the curves not changing shape but simply getting steeper in response to increased cylinder pressure.
Occasionally listing just the peak numbers gives a surprising clear big-picture look at a test. This is one such time, as the peak rear wheel horsepower numbers show:
|Pulley||Stock TB||Kenne Bell TB||Gain|
It's especially clear from the synopsis that the large throttle body pays off increasingly large dividends as the power level goes up.
For the record, the test car was nearly stock save for the Kenne Bell equipment. Specifically, stock headers and catalytic converters were used; a Pypes after-cat kit gives it a muscular tone but likely didn't materially affect the results. A Kenne Bell Boost-a-Pump aids delivery of pump gas, doped to about 100 octane with canned octane boosters; and the ignition remains stock.
Accommodating the wildly different stock and 168mm throttle bodies on the intake tube requ
...Flush hardware and O-ring gaskets are features of both. Doesn’t the stock throttle body
Small as it looks, the stock 80mm throttle body is all that’s truly needed up to 600 hp, a